Cardiovascular disease (CVD) has been the leading cause of death since 1935 and it is anticipated that by 2030, about 40% of the US population will suffer from some type of cardiovascular disease. The burden of cognitive decline, which has been linked to traditional cardiovascular risk factors, is also expected to rise as the US population ages. Cardiovascular disease risk factors present in midlife have been associated with cognitive decline in older ages. Inflammatory and oxidative processes have been proposed as underlying mechanisms that may link CVD and cognitive decline. Measures that can protect against or mitigate CVD and cognitive decline are of great importance to public health. Diets high in plant-based foods, such as the Mediterranean diet, have been associated with a lower incidence of acute coronary heart disease, stroke events, and cognitive impairment. Flavonoids, which are bioactive, non-nutrient, polyphenolic compounds found in vascular plants, may explain some of the protective effects of plant-based diets. Several protective mechanisms have been proposed, based on the pleiotropic nature of flavonoids, which include antiinflammatory and antioxidant properties. Previous epidemiologic studies have yielded mixed evidence regarding the strength of the association between increased flavonoid intake and cardiovascular health. The overarching goal of this research proposal is to evaluate the role of dietary flavonoids in the development of CVD and cognitive impairment. Using data from the REasons for Geographic and Regional Differences in Stroke (REGARDS) study (n=30,0000), we will evaluate the association between dietary flavonoid intake and incident CVD and incident cognitive impairment. Using data from the Mental Stress Ischemia: Prognosis and Genetic Influences (MIPS) study (n=650), we will evaluate the association between dietary flavonoid intake and recurrent CVD. Results from the proposed research will clarify the role of dietary flavonoids in cardiovascular and neurodegenerative disease. Also, the results will address gaps in knowledge about the associations of interest in non-Hispanic black populations. This information will be useful in public health interventions seeking to reduce CVD burden and disparities in CVD disease.